1. Technical Field
The present invention relates to the use of Tamarix trees for production of biomass fuel.
2. Description of Related Art
Global warming may be the most acute ecological problem the world is facing. Mankind may be contributing to global warming through an ever increasing production of greenhouse gases (GHG) e.g. carbon dioxide, which accumulate in the atmosphere and increase the greenhouse effect which tends to increase the average global temperature. Combustion of fossil fuels increases carbon dioxide in the atmosphere. Burning of fossil fuels is arguably a major source of greenhouse gases in the atmosphere. Replacing fossil fuels by renewable fuels or renewable sources of energy may be the most effective way to reduce the emission of greenhouse gases and slow down the global warming process.
The four major types of renewable energy include hydro power, solar power, wind power and biomass. Biomass is biological material of animal or vegetable origins, such as wood, agricultural crops and waste, fats and oils and any other burnable biological material. Biomass is commonly plant matter which is used to generate heat which may be used for the generation of electricity. The most conventional way of using biomass is as solid fuel for direct incineration. The most common biomass sources are forest trees and residues, yard clippings, municipal and agricultural waste and energy crops. Biomass fuel is normally “carbon neutral” because the amount of carbon which is emitted at the time of its burning is equal (or less) to the amount which is absorbed by the plant in its process of vegetative growth. Furthermore, growing energy crops creates a “carbon sink” through “terrestrial carbon sequestration” by increasing soil organic matter/carbon through crop root systems. In addition, since plants and trees absorb and store atmospheric carbon as they grow, growing and using biomass energy crops actively reduces the level of carbon dioxide in the atmosphere in direct proportion to the amount of biomass produced as compared to the original amount of biomass existed before on the same land. More than half of the carbon dioxide emitted annually from fossil-fuel combustion could be “sequestered” by planting high yield biomass crops on available marginal lands in different parts of the world. In addition, energy crops normally contain very low amounts of sulfur, which is a major cause for acid rain and has significantly less nitrogen (NOx), which is a major cause for smog. Energy crops normally have very low ash content. The reason why cultivation of energy crops is not one of the world's most widely used approach is twofold. Firstly the available amount of legitimate forest and agriculture biomass is very limited and secondly after decades of research in attempt to produce “Super Trees” the results, in terms of yield, has been rather disappointing and as a direct consequence the cost remain too high.
Biomass is the only type of renewable energy in which its scope of production is dependent collectively on humanity's decisions and priorities. If, for example, the agriculture areas in the Midwest of the USA will be used for production of biomass they can produce enough biomass to replace all the coal used in the USA (1.1 billion tons per year). However this approach, if adopted, may result in an international disaster as it may dramatically decrease the amount of basic foods available in the world. Moreover, due to low yield of biomass under the climatic conditions in the US Midwest the cost of electricity produced from burning biomass may be more than tripled compared to that of coal.
As has been already commercially demonstrated, solid biomass fuel may replace at least 30% of the coal in coal-fired power plants. The total consumption of coal worldwide is around 5 billion tons per year and therefore the total potential demand for solid biomass fuel, in the world; in the co-firing segment alone is 1.5 billion tons. However, since the calorific value of biomass is 30% lower than that of coal, the actual potential demand is around 2.0 billion tons per year.
Presently, in most cases, growing of biomass as a stand-alone short-rotation crop (SRC) is not economically viable due to not high enough biomass yield. The prevailing procedure is to grow short rotation biomass crops as “co-product” which is normally defined as any material or benefit that result from production of another marketable commodity. Most, if not all, of the short rotation crop for energy presently grown around the world are highly dependent on the availability of heavy subsidies or are in the form of co-product. The highest biomass yield reported is about 35 metric tons per hectare, per year. The yield of 35 metric tons per hectare, per year, even under energy high prices conditions, is not enough to make this crop economically viable. The highest yield achieved under commercial cultivation of biomass crops is typically no more than 22 metric tons per hectare, per year.
Around one third of continental water in the world is saline. Saline (or brackish) water is defined as in land water which is too salty for being used as drinking water and as irrigation water for most available crops. Large parts of the world land are in desert areas where the soil quality and climatic conditions make the cultivation of all available crops practically impossible.
There is thus a need for and it would be advantageous to have a method for biomass production that does not require arable land and/or fresh water required for food crops. The method produces biomass in high enough yields to be supplied to a user at an affordable cost.